This relates generally to imaging systems and, more particularly, to imaging systems that use hole-based photodiodes.
Modern electronic devices such as cellular telephones, cameras, and computers often use digital image sensors. Imager sensors (sometimes referred to as imagers) may be formed from a two-dimensional array of image sensing pixels. Each pixel includes a photosensitive element that receives incident photons (light) and converts the photons into electrical signals. Image sensors are sometimes designed to provide images to electronic devices using a Joint Photographic Experts Group (JPEG) format.
Image sensors may be complementary metal-oxide semiconductor (CMOS) image sensors. Conventional CMOS image sensors may include an n-type pinned photodiode to collect photoelectrons. Conventional CMOS image sensors may also use n-channel metal-oxide-semiconductor field-effect transistors (NMOS transistors). However, these conventional CMOS image sensors may experience high dark current and pixel readout noise.
It would therefore be desirable to be able to provide improved pixel designs for image sensors.